Energy Absorbing System for Safeguarding Structures from Disruptive Forces

ABSTRACT

The invention is a system and method for automatically adjusting the resonance frequency of an energy absorbing device in response to a disruptive force. By configuring an energy absorbing device for automatic response tuning, utilizing a controller coupled to one or more sensors for processing a determination primarily based on sensing data, the natural period of an overall structure may be adjusted (i.e. increased or decreased) so that the acceleration response of the structure is decreased upon being subjected to a disruptive force, for example, high winds, a blast from an explosion, or a seismic force caused by an earthquake.

PRIORITY NOTICE

The present application is a continuation application, which claimspriority under 35 U.S.C. §120 to U.S. patent application Ser. No.13/408,862, filed on Feb. 29, 2012, which is a continuation applicationof U.S. patent application Ser. No. 12/098,316, filed on Apr. 4, 2008,the disclosure of which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to a system and method forautomatically adjusting the resonance frequency of an energy absorbingdevice in response to a disruptive force, and more specifically,configuring an energy absorbing device for automatic response tuningutilizing a controller coupled to one or more sensors, for generating acontrol signal based on sensing data, in order to increase or decreasethe natural period of an overall structure so that the accelerationresponse of the structure is decreased upon being subjected to adisruptive force.

BACKGROUND OF THE INVENTION

Traditionally, the conventional approach to protecting structures fromdisruptive forces, for example strong winds, seismic vibrations, orexplosions, has been to strengthen structures themselves—either byfortifying a structure's walls and foundations, or simply by utilizingstronger, perhaps heavier materials. In the last few decades, thoseskilled in the art have understood that such methods are not appropriatefor medium to tall structures due to the frequencies that are generatedthrough, for example, buildings or bridges, which ultimately cause thestructures to collapse. These old methods of strengthening structuresare thus not as effective for any structure as newly developed methods.

Many efforts have also been directed to implementing various types ofdevices that absorb energy from a disruptive force in order to dampenthe disruptive vibrations and prevent vibration forces from damagingstructural components or entire structures altogether.

Relatively recent, base isolation devices have been developed to isolateor decouple structures from disruptive forces, such as seismic forcesproduced during an earthquake, or strong winds, particularly againststructures such as buildings. However, these systems have provenexpensive and inadequate for smaller structures such as low to mid-risebuildings and family homes.

In addition to the higher cost that makes base isolation and similardevices inadequate for low to mid-rise buildings (i.e. most contractorswon't implement such devices in low to mid-rise buildings or familyhomes in order to keep budgets low), current designs are difficult topredict mathematically, which poses a major problem for engineers.

For structure designs that do implement complex base isolation systems,for example corporate or government buildings, traditional passivesystems have been used. However, these traditional passive systemscurrently in use may react to light winds and occupancy loads in amanner that causes the building to sway slightly. This sway may be feltby the occupants and often causes an undesirable “sea sick” feeling.Thus, since such passive systems' sensitivity may not be adjusted, thestructures or building which implement such technology are frequentlyaffected with undesirable motion.

Another one of the problems associated with past efforts to protect astructure from disruptive forces is that it is difficult, if notimpossible, to anticipate the degree of strength of the disruptiveforce, as well as the particular movements of the disruptive force inand around a structure. An energy absorbing device may be able to infact absorb the energy from a disruptive force; however, if thedisruptive force is extremely large or if the structure is vibrated invarying directions, the damage may ultimately lead to the collapse ofthe structure unless immediate maintenance or adjustments are madefollowing the disruptive event—this is often expensive and requires useof limited resources (i.e. deploying personnel such as technicians,engineers, experts, etc.).

Thus, while present practices have employed methods to repair and adjuststructures following disruptive events, for example, an earthquake, or ablast from an explosion, such methods require significant man power andexpenditure of valuable resources: trained personnel, eligibleengineers, and city inspectors are usually deployed even in response tominor events due to the lack of information available about a particularstructure's stability following such an event.

Furthermore, current systems require maintenance during which energyabsorbing devices installed within a structure must be routinelyinspected in order to assure that the energy absorption system isproperly functioning.

Therefore, there is a need in the art for a system and method that iscost effective, requires less maintenance, and is capable of selfadjustment and easily adaptable to forces inflicted during an eventwherein disruptive forces are applied to a structure. It is to theseends that the present invention has been developed.

SUMMARY OF THE INVENTION

To minimize the limitations in the prior art, and to minimize otherlimitations that will be apparent upon reading and understanding thepresent specification, the present invention describes a system andmethod for automatically adjusting the resonance frequency of an energyabsorbing device in response to a disruptive force.

An automatic energy dissipation system, in accordance with the presentinvention comprises a sensor for detecting a disruptive force applied toa structure; a processor connected to said sensor, configured fordetermining a control signal based on a sensing data received from saidsensor; an energy absorbing device for coupling to said structure; andan actuator, coupled to said processor and connected to said energyabsorbing device, for tuning said energy absorbing device based on saidcontrol signal generated by said processor, wherein said tuning of saidenergy absorbing device comprises altering a resonance frequency of saidstructure to reduce a structural response to said disruptive forceapplied to said structure.

One method for protecting a structure from disruptive forces, inaccordance with the present invention, comprises the steps of generatinga sensing data related to a disruptive force; receiving said sensingdata; generating a control signal from a determination based on saidsensing data; and tuning an energy absorbing device based on saidcontrol signal.

It is an objective of the present invention to enhance the protection ofa structure that may be subjected to varying types of disruptive forcesby implementing an automatic response system equipped with sensors andself modifying energy absorption devices.

It is another objective of the present invention to improve a retainingwall's ability to resist and respond to the surge of earth or groundpressures, for example seismic pressures, by implementing automatedactuators adapted for tuning base isolation or energy dissipationdevices.

It is yet another objective of the present invention to provide anactive way of protecting a structure from varying degrees of force thatwould typically be able to severely damage or collapse a structure.

It is yet another objective of the present invention to provide anautomatic corrective response to a disruptive event by gathering sensingdata pertaining to disruptive forces, and altering a resonance frequencybased on the sensing data, by tuning an energy absorbing device coupledto a structure.

It is yet another objective of the present invention to automaticallytune an energy absorbing device for damping the effect of a disruptiveforce thereby adjusting a resonance frequency of a structure to preventdamage.

It is yet another objective of the present invention to provide anautomatic response system for simultaneously tuning multiple energyabsorbing devices coupled to one or more structures.

It is yet another object of the present invention to provide a dynamicautomated energy dissipation system that may be implemented in a varietyof applications with few or no modifications.

It is yet another objective of the present invention to provide a way ofadjusting the resonance frequency of an energy absorbing device attachedto a structure that is cost-effective for use in family homes andbuildings ranging from one to four stories.

Furthermore, it is yet another objective of the present invention toprovide an automated energy absorbing system configuration comprising ofa plurality of base isolation units, which may be deployed in a mannerso as to cover a multitude of structures while minimizing costs andprotecting a greater area from disruptive forces.

These and many other advantages and features of the present inventionare described herein with specificity so as to make the presentinvention understandable to one of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Elements in the figures have not necessarily been drawn to scale inorder to enhance their clarity and improve understanding of thesevarious elements and embodiments of the invention. Furthermore, elementsthat are known to be common and well understood to those in the industryare not depicted in order to provide a clear view of the variousembodiments of the invention.

FIG. 1( a) illustrates a block diagram of the system and method foradjusting a resonance frequency of an energy absorbing device attachedto a structure, including a structure containing multiple energyabsorbing devices, with multiple actuators adapted to the energyabsorbing devices, a controller coupled to the actuators, and a sensorcoupled to the controller, in accordance with one embodiment of thepresent invention.

FIG. 1( b) illustrates another block diagram of the system for adjustinga resonance frequency of an energy absorbing device attached to astructure, including a structure containing multiple energy absorbingdevices, each of which are coupled with multiple actuators as well assensors coupled to each actuator, and all of which are coupled to acontroller, in accordance with another embodiment of the presentinvention.

FIG. 2 is a graphical representation of basic principles well known andunderstood by those skilled in the art, showing how damping andincreasing the period of a structure will decrease an accelerationresponse to a disruptive force thereby minimizing damage to structuralcomponents.

FIG. 3( a) and FIG. 3( b) illustrate an exemplary configuration forplacement of various energy absorbing devices coupled to actuators inaccordance with one embodiment of the present invention.

FIG. 4( a) is a front view of an energy absorbing apparatus installedwithin a structure, for example between the floor and foundation of abuilding, in accordance with one embodiment of the present invention.

FIG. 4( b) is a side view of an energy absorbing apparatus installedwithin a structure, for example between the floor and foundation of abuilding, in accordance with one embodiment of the present invention.

FIG. 4( c) is a close-up view of a lower right portion of the energyabsorbing apparatus illustrated in FIG. 1( b), depicting an exemplaryway to assemble the various components of one embodiment of an energyabsorbing apparatus, and a desired notch or spacing to add flexibilityand decrease stiffness, between the base of the apparatus and a supportmember of a structure, for example a foundation of a building, inaccordance with an exemplary embodiment of the present invention.

FIG. 4( d) is a cross-sectional view of the energy absorbing apparatusdepicted in FIGS. 4( a)-(c), illustrating its internal composition.

FIG. 5( a) is an exploded view of an energy absorbing apparatus, such asa base isolator, displaying its various components and parts.

FIG. 5( b) is an elevated plane view of a fully-assembled energyabsorbing device, depicted in FIG. 5( a).

FIG. 6 displays a directional displacement effect on one embodiment of abase isolator in accordance with the present invention, as disruptiveforces are applied, for example seismic forces.

FIG. 7 and FIG. 8 illustrate diagrams of two grids representing anentire city block in which one or more structures, with actuators placedon each of the multiple energy absorbing devices, such as baseisolators, that are placed strategically in and around the structure,and each which may respond to a different resonance frequency dependingon the direction of movement of the disruptive force that can occur onthe structure, for example, in a north-south direction or an east-westdirection, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following discussion that addresses a number of embodiments andapplications of the present invention, reference is made to theaccompanying drawings that form a part hereof, in which is shown by wayof illustration specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand changes may be made without departing from the scope of the presentinvention.

The present disclosure teaches a system and method that utilizes acontroller, coupled to one or more sensors, for example seismic sensors,configured to receive sensing data and process necessary information inorder to generate and relay commands to one or more energy absorbingdevices implemented into one or more structures. By coupling one or moreactuators to each energy absorbing device, the controller is able toprocess and generate control signals, communicate with each actuator,and actuate any necessary components to make adjustments required byeach energy absorbing device in order to decrease a disruptive responseof a structure.

The calculations or determinations processed by the controller arecommunicated to each actuator coupled to corresponding energy absorbingdevices, wherein any required tuning is therefore in response, or inanticipation, to the disruptive force, thereby constantly makingadjustments and reconfiguring parameters for each energy absorbingdevice in order to alter or modify a critical structural state, forexample the period or resonance frequency of a structure, during adisruptive event (e.g. an earthquake, high winds, or an explosion).

Furthermore, depending on the applications for which a system inaccordance with the present invention may be implemented, it isunderstood that different configurations of the various elements may beemployed without deviation or limiting the scope of the presentinvention. For example, the system and method disclosed herein maycomprise of a controller, one or more sensors and: a single actuatorcoupled to a single energy absorbing device; multiple actuators toadjust or tune a single energy absorbing device; a single actuator foradjusting or tuning multiple energy absorbing devices; or multipleactuators to adjust or tune multiple energy absorbing devices.

It is understood that in the present disclosure, an automatic responseenergy absorbing system may be implemented with any device or systemdesigned to absorb or dissipate energy from a disruptive force away froma structure. An automatic response, in accordance with the presentinvention, may comprise tuning an energy absorbing system in responseto, or in anticipation of a disruptive force. Alternatively, anautomatic response may also include a self adjustment performed by anautomated system, or an automatic response generated from a user input.

Tuning, as defined in the present disclosure, may refer to a process ofselecting appropriate genetic operators and their respective parametersto suit a problem; a process of changing the parameters of a device or asystem to achieve a specified or improved performance; a process ofestablishing a desired frequency of a system; or a variety ofadjustments, modifications, alterations, or calibration to optimizeperformance of an overall system.

An energy absorbing system may include without limitation, a passiveenergy control system, an active energy control system, a semi-activeenergy control system, a hybrid control system, or any other type ofknown energy control system directed at dissipating energy away from astructure or protecting structural integrity for a variety ofapplications, without deviating from the scope of the present invention.

FIGS. 1( a) and 1(b) illustrate two embodiments of an automaticdisruptive energy response system configured for tuning a plurality ofenergy absorbing devices 104, which may be coupled to one or morestructures for dissipating a destructive force, or isolating one or morestructures from a disruptive energy in order to preserve structuralintegrity.

Turning first to FIG. 1( a), system 100 comprises a plurality of energyabsorbing devices 104 coupled to a plurality of actuators 103, whichhave been configured to receive commands or control signals fromcontroller 102. System 100 further comprises sensor 101 for receivingsensing data pertaining to a disruptive force that may affect structure106's integrity. It is that sensing data, along with structuralinformation pertaining structure 106, which controller 102 processes inorder to adjust each energy absorbing device coupled to structure 106.

Although it is understood that typically structure 106 may be a generalbuilding, structure 106 may alternatively comprise a variety ofstructures without limiting the scope of the present invention.

For example, and without deviating from the scope of the presentinvention, structure 106 may be a small office building, a warehouse, afamily home, a sky scraper, a network of buildings within a city block,a parking structure, a recreational building, a stadium, an undergroundfacility, an armored vehicle, any type of water retaining wall, a dam, alevee, a protective container for transporting sensitive materials, orany other type of structure for which an energy dissipation or baseisolation system may be implemented in order to preserve structure 106'sstructural integrity and thereby protect any entities or productssituated within and around structure 106 during a disruptive event.

Controller 102 may be any type of known controller or processorconfigured for executing known or proprietarily created formulas,equations or algorithms, which may be necessary to process or calculaterequired adjustments for tuning energy absorbing devices 104. A primarypurpose for controller 102 is to process certain determinations based onknown or unknown constants and variables. For example, and withoutlimiting the scope of the present invention, controller 102 may processinformation pertaining to the natural period of structure 106, a defaultsystem resonance frequency for structure 106, or a magnitude of adisruptive force detected by sensor 101. Furthermore, it may bedesirable for controller 102 to process any other information pertainingto system 100 such as the number of actuators within system 100, thenumber of energy absorbing devices 104 within system 100, a locationwherein each device is coupled to structure 106, and possibly a numberof structural components comprising structure 106 which may be managedby system 100.

Typically, controller 102 may have access to a database containing allrelevant information pertaining to system 100. For example, and withoutlimiting the scope of the present invention, such data may include thenumber of devices coupled to a structure, the configuration of energydevices 104, the number of actuators 103, structural components, or anyother type of relevant information that controller 102 may require inprocessing and making relevant determinations whether during adisruptive event or during maintenance of system 100.

In one embodiment, controller 102 comprises a server with multiplecomputers in charge of various base isolation systems within one or morelocations. This may be desirable to centralize a wide system whichcovers a number of structures. In another embodiment, controller 102 isa simple processor situated within a single structure which has beenequipped with one or more energy absorbing devices 104 and actuators103.

In yet another embodiment, controller 102 is a multi server systemcomprising a database of various locations capable of managing andadministrating a variety of base isolation systems deployed throughoutan entire city block (such desirable configuration for one embodiment ofthe present invention may be implemented as described in detail withreference to FIG. 1( b).

Typically, controller 102 may be monitored and controlled manually by anauthorized user such as a system's manager or administratorknowledgeable in engineering and structural components of system 100.This may be achieved by implementing a monitoring device or userinterface on which such authorized user may oversee, manage, and monitorsystem 100's specifications, parameters, capabilities or performancelevels. In an exemplary embodiment, controller 102 is connected to userinterface 105 as illustrated in FIGS. 1( a) and (b).

User interface 105 may allow an authorized user such as a qualifiedengineer to access information necessary for calibrating actuators 103or sensor 101. User interface 105 may allow users to update software andrepair errors or damage that occur within controller 102 or anywherethroughout system 100. User interface 105 may be simple interface whichallows data retrieval and data input, or may comprise a graphical userinterface to facilitate human interaction with system 100 withoutdeviating from the scope of the present invention.

In one embodiment, user interface 105 may be a local user interfacelocally connected to controller 102. In another embodiment, userinterface 105 may further comprise a local interface in addition to aweb-based graphical user interface, which may be accessed through anetwork interface from a remote location thereby allowing an authorizeuser to monitor, manage, maintain, update, or control system 100 viauser input provided to controller 102.

Controller 102 is configured to receive sensory information from sensor101, which has been configured to generate sensing data pertaining to adisruptive force's properties; for example and without limitation: aforce magnitude, direction, or epicenter from which a disruptive forcemay have originated.

Sensor 101 may be any type of sensor known in the field which may beutilized to receive any sensing data pertaining to a disruptive forcesuch as vibrations from seismic forces, vibrations from high winds,forces generated from the blast of an explosion, or any other type ofdisruptive force which may need processing by system 100, particularlyin relation to structure 106.

Typically, sensor 101 is an instrument configured for recording motionsof the ground, including those seismic waves generated by earthquakes,explosions, or other seismic sources. Additionally, depending on theapplications of system 100, sensor 100 may be configured to detectground vibrations resulting from oncoming vehicles such as armoredtrucks or military vehicles.

In one embodiment sensor 101 is a component forming part of anearthquake warning system further comprising of accelerometers,communication mediums, (i.e. to communicate with computers includingcontroller 102), and alarms that are devised for regional notificationof a substantial earthquake while its disruptive forces are in progress.Pre-existing high speed communications systems and computers whichcollect sensor readings may be implemented with system 100 so thatcontroller 102 may be programmed to detect the likely strength andprogression of for example, a seismic event.

In another embodiment, another variation of sensor 101 comprises asub-system of electronic sensors, amplifiers, and recording instrumentswhich are configured to communicate with controller 102. Typically,these components of sensor 101 are known instruments which are broadbandin nature and cover a wide range of frequencies (i.e. some seismometerscan measure motions with frequencies from 30 Hz (0.03 seconds per cycle)to 1/850 Hz (850 seconds per cycle), however implementing any type ofsensor equipment with sensor 101 does not deviate from the scope of thepresent invention.

As way of example, other variations of sensor 101 may comprise use ofknown horizontal instruments, or known vertical instruments that useconstant-force suspension. Alternatively, sensor 101 may employ moderninstruments which use a “triaxial” design, in which there are threeidentical sensors to measure motion at the same angle to the vertical,but along directions 120 degrees apart.

In yet another embodiment, sensor 101 comprises a teleseismometer whichcan record a very broad range of frequencies.

Sensor 101 may comprise a single sensor connected to structure 106itself, or may be located in a remote location. For example, and withoutdeviating from the scope of the present invention, sensor 101 maycomprise a network of sensors positioned in a manner so as totriangulate the origin and direction of a particular disruptive forceapproaching structure 106.

In an exemplary embodiment, sensor 101 may invoke a force accelerometerand be interconnected with other seismometers for precisely locating inthree dimensions the source of a disruptive force.

Furthermore, sensor 101 may be an analog seismograph that requiresanalog recording equipment, possibly including an analog-to-digitalconverter. However, it may be desirable to implement sensor 101 withdigital seismographs that simply plug in to controller 102 to presentany sensing data in standard digital forms-making communication betweensensor 101 and controller 102 less complex, more accurate, and moreefficient. All these alternative sensor configurations and sensorcomponents and methods are known and may be implemented in system 100without deviating from the scope of the present invention.

The sensing data retrieved by sensor 101 must ultimately be processedand calculated in order for controller 102 to communicate anydeterminations or control signals generated from said sensor data on toone or more actuators 103 in system 100. These actuators become the armsand legs for controller 102 to be able to tune (i.e. activate, adjust,or calibrate) each individual energy absorbing device 104.

In the present disclosure, an actuator may be, without limitation: anyapparatus or device, whether electric, magnetic, or mechanical, formoving or controlling a mechanism, apparatus, instrument, or system. Anactuator in the present disclosure may be utilized to introduce motion,or to clamp an object or component so as to prevent motion, or may beany device which transform an input signal (i.e. an electrical signalfrom controller 102) into motion.

For example, and without limiting the scope of the present invention,actuators 103 may comprise of motors, pneumatic actuators, hydraulicpistons, relays, linear actuators, electric actuators, rotary actuators,yoke actuators, rack and pinion actuators, or any other type of actuatorwhich may be implemented with an energy absorbing device in accordancewith the present invention.

Actuators 103 may therefore be any type of known actuators which canhandle several types of functions to adjust, calibrate, activate, ormodify parameters of any one of the multiple energy absorbing devices104. In an exemplary embodiment, a rotary actuator may be usedparticularly when circular motions are needed (see FIG. 4( a)-(c) below)to adjust or tune energy absorbing devices 104 in response or inanticipation of a disruptive event.

Actuators 103 may be coupled to a single energy absorbing device, ormultiple devices depending on the nature of structure 106, but mostimportantly, actuators 103's configuration in relation to energyabsorbing devices 104 may depend primarily on the kinds of componentsand designs that make up energy absorbing devices 104.

Energy absorbing devices 103 may comprise seismic isolation devices orenergy dissipation devices depending on the nature of structure 106.Furthermore, energy absorbing devices 104 may comprise multiple types ofenergy absorbing techniques (i.e. energy dissipation or base isolation).For example and without deviating from the scope of the presentinvention, energy absorbing devices 104 may include base isolatorsplaced at a base of structure 106 to decouple structure 106 fromdamaging properties of a disruptive force, so as to prevent structure106's superstructure from absorbing the disruptive energy in addition toproviding substantive damping. Furthermore energy absorbing devices 104may include energy dissipation devices placed within frames or walls ofstructure 106 to provide supplemental viscous damping or hystereticdamping in order to significantly reduce a structural response to themotions from the disruptive force.

Therefore, energy absorbing devices 104 may include a variety of devicesto help isolate and dissipate energy away from structure 106, includingbut not limited to general base isolators, flexural beam devices,lead-rubber devices, lead extrusion devices, flexural plate devices,torsional beam devices, viscoelastic dampers, hydraulic devices,friction-slip devices, metallic yielding devices, shape-memory alloydevices, or any other type of devices capable of aiding in theisolation, absorption, or dissipation of a large portion of a disruptiveenergy through any means such as inelastic deformations or frictionconcentrated in the energy absorbing devices, thereby protectingstructure 106 from damage.

In an exemplary embodiment, structure 106 comprises a building andenergy absorbing devices 104 are primarily base isolators which may betuned by actuators 103 upon command from controller 102. For example,and in no way limiting the scope of the present invention, during anearthquake, and in response to control signals generated by controller102, energy absorbing devices 104 are calibrated or tuned by actuators103 to increase the natural period of the overall structure 106, therebydecreasing the acceleration response of structure 106. Since the naturalfrequency of structure 106 is dominated by the natural frequency of theisolator, controller 102 must evaluate (through processing any sensordata received from sensor 101) the effective or equivalent stiffness anddamping ration for each and every one of energy absorbing devices 104;notably, any damping generated by energy absorbing devices 104 willfurther decrease structure 106's acceleration response, thus a desirablefeature to be implemented with every one of energy absorbing devices 104utilized with system 100.

By implementing one or more actuators 103 with any type of the abovementioned energy absorbing devices 104, controller 102 may modify,calibrate, adjust or tune each device to properly respond to adisruptive event by means of communicating any generated signals to oneor more actuators 103 coupled to energy absorbing devices 104.

Typically, as in the illustrated embodiment, the entire set of energyabsorbing devices 104 and actuators 103 communicate with controller 102via any type of known communication methods without deviating from thescope of the present invention. In one embodiment, controller 102communicates with actuators 103 via a wired system. In anotherembodiment, controller 102 communicates with actuators 103 via awireless network. And in yet another embodiment, actuators 103communicate with each other via a wired network and send and receive anyinformation regarding energy absorbing devices 104 to and fromcontroller 102 utilizing a wireless network bridge.

Referring briefly to FIG. 1( b), another embodiment utilizing the samecomponents is illustrated by way of example. The illustrated embodimentcomprises of multiple sensors 115 which are utilized in order toretrieve sensing data more specifically related to a particular locationwherein each of a plurality of energy absorbing devices 104 has beenimplemented into structure 106. Since a disruptive force may affectdifferent components of structure 106 with varying levels of force andin varying directions, implementing localized sensors 115 may be adesirable configuration to gather data about a particular location ofstructure 106 with greater accuracy.

For example, and without deviating from the scope of the presentinvention, different materials may be utilized in some sections orportions of structure 106, thus a disruptive force may affect distinctareas of structure 106 with variable forces, sensors 115 may gather dataand send such data to controller 102 so that energy absorbing devices104 may be tuned in accordance with the force being asserted to thatparticular section or portion of structure 106.

FIG. 2 illustrates a simple chart depicting a response spectra of astructure retrofitted with energy absorbing devices. Energy absorbingdevices such as base isolators, help in reducing disruptive forces bychanging the structure's fundamental period to avoid resonance with thepredominant frequency contents of the disrupted forces.

A controller in accordance with the present invention (such ascontroller 101) may be configured to tune, adjust, or calibrate eachenergy absorbing device coupled within a structure to change the periodof the structure accordingly in response or in anticipation of adisruptive event. A disruptive event may be strong winds, an earthquake,an explosion, or a surge of water directed towards a structure.

FIG. 2 is a simple graphical representation of basic principles wellknown and understood by those skilled in the art. Therefore the presentdisclosure will not be directed to explaining the various complexcalculations and determinations required for controller 101 to processwhen generating control signals in tuning energy devices in accordancewith the present invention.

However, in one embodiment and by way of example, controller 101 mayprocess the effective period of structure 106 using a known formulashown below to determine the effective period. The effective period ofthe isolated structure 106, T_(D), may be determined using thedeformational characteristics of the isolation system used, inaccordance with the equation shown:

$\begin{matrix}{T_{D} = {2\; \pi \sqrt{\frac{W}{k_{Dmin}g}}}} & (1)\end{matrix}$

where:

W is total seismic dead load weight of the structure above the isolationinterface (kip or kN), k_(Dmin) is the minimum effective stiffness, inkips/inch (kN/mm), of the isolation system at the design displacement inthe horizontal direction under consideration, g is the acceleration ofgravity, and the units of the acceleration of gravity, g, are in./sec²(mm/sec²) if the units of the design displacement, D_(D), are in inches(mm).

Similar known methods may also be processed by controller 102 todetermine structure 106's effective period at a maximum displacement.The effective period of such isolated structure 106 at a maximumdisplacement, T_(M), may be determined using the deformationalcharacteristics of the isolation system in accordance with the followingequation:

$\begin{matrix}{T_{M} = {2\; \pi \sqrt{\frac{W}{k_{Mmin}g}}}} & (2)\end{matrix}$

where:

W is the total seismic dead load weight of the structure above theisolation interface, k_(Mmin) is the minimum effective stiffness, inkips/inch (kN/mm), of the isolation system at the maximum displacementin the horizontal direction under consideration, and g is theacceleration due to gravity. The units of the acceleration of gravity,g, are in./sec² (mm/sec²) if the units of the design displacement,D_(D), are inches (mm).

Again, these are known methods of processing or calculating thenecessary variables system 100 may require in order to tune energyabsorbing devices 104. It is understood that other methods and formulaswhich are well known to one of ordinary skill in the art, may be madeavailable and implemented with system 100 so that controller 102,through the use of equations, algorithms, or formulas, may tune eachdevice in response or in anticipation of a disruptive event, or duringroutine maintenance of system 100.

In another embodiment, for example wherein structure 106 comprises abuilding, controller 102 may further take into account the number offloors that make up structure 106. Since damage to buildings duringseismic forces is most likely to occur when the shaking frequency of theground matches the shaking frequency of the building, controller 102 mayuse such structural information to determine at what frequency structure106 will be most susceptible to damage and tune energy absorbing devicesaccordingly. For example, and without deviating from the scope of thepresent invention, the following table illustrates the general principalthat a building's frequency is about 10 Hz (vibrations per second)divided by the number of floors. Controller 102 may therefore utilizethis information to determine at which frequency structure 106 may bemost sensitive to, for example, a seismic force.

TABLE 1 Number of Frequency Period Floors (Hz) (seconds) 1 10.0 0.1 25.0 0.2 5 2.0 0.5 10 1.0 1.0 30 0.3 3.3 100 0.1 10.0

FIG. 3( a) and FIG. 3( b) illustrate an exemplary configuration forplacement of various energy absorbing devices coupled to actuators inaccordance with one embodiment of the present invention. Morespecifically, FIG. 3( a) is a diagram representing a top view of astructure's support beams or frame and FIG. 3( b) is a diagramrepresenting a side view thereof, wherein the structure rests on severalenergy absorbing devices coupled to actuators, for example baseisolators coupled to actuator units, over the structure's foundation,and wherein the structure's superstructure is suspended or isolated fromthe ground and foundation. Although this represents a typicalconfiguration for placement of energy absorbing devices within astructure, actuators and sensors have been implemented to improve theoverall system in accordance with one exemplary embodiment of thepresent invention.

Typically, support beams (or comparable structural components) ofsuperstructure 301 are adapted with various energy absorbing devices—inthis case, various base isolators 302, 303, 304, and 305 (andcorresponding actuators 302 a, 303 a, 304 a, and 305 a), which have beencoupled in a manner so that structure 300's superstructure 301 issuspended or isolated from foundation 306.

While placement of base isolators 302, 303, 304 and 305 will depend onthe particular requirements of structure 300, typically base isolators302, 303, 304 and 305 will be implemented between foundation 306 andsuperstructure 301. Furthermore, other energy absorbing devices may beimplemented throughout structure 300. For example, FIG. 3 (b)illustrates a diagram of a side view of structure 300 wherein verticalbeams, or support beams 308, further make up superstructure 301 ofstructure 300. Support beams 308 are retrofitted with energy absorbingdevices 307 coupled to actuators 307 a in a manner so that energyabsorbing devices 307 may minimize an acceleration response, dissipate adisruptive energy, alter an overall period of structure 300, or provideany other function that will further preserve structure 300's structuralintegrity during a disruptive event.

A sensor and control system 310 is adapted to communicate with actuators302 a, 303 a, 304 a, 305 a, and 307 a via a communication link 309.Communication link 307 may be a conduit carrying wires for power andcommunication, or may be a wireless network that is able to transmitinformation between each device and system 310.

Placement of actuators 307 a for energy absorbing devices 307 oractuators 302 a, 303 a, 304 a, and 305 a for base isolators 302, 303,304 and 305 assure an automatic tuning of the various devices inresponse or in anticipation of a disruptive force directed towardsstructure 300.

If the magnitude of a disruptive force occurs with greater force on oneend of structure 300 where, for example, base isolators 304 and 305 arein place, the resonance frequency of structure 300 resulting from thedisruptive force may be offset by the tuning only those devices. Thus,control signals to base isolators 302 and 303 may differ than controlsignals sent to base isolators 304 and 305 to compensate for thedirection of the path of the incoming disruptive force.

Similarly, if the magnitude of a disruptive force affects structure 300equilaterally throughout structure 300, all base isolators 302, 303,304, and 305 may be tuned equally in order to offset the constantdisruptive resonance frequency applied to structure 300.

FIG. 4( a)-FIG. 4( d) illustrate an exemplary embodiment of a baseisolator, which may be installed within a structure, for example betweenthe floor and foundation of a building, adapted for tuning byimplementing actuators coupled to one or more components of the baseisolator.

FIG. 4( a) is a front view of base isolator 400 installed within astructure; FIG. 4( b) is a side view thereof, further illustrating onealternative installation feature which makes use of spacing 411 tominimize stiffness to the apparatus perpendicular to the direction ofloading; FIG. 4( c) is a close-up view of a lower right portion of baseisolator 400 illustrated in FIG. 4( b), depicting an exemplary way toassemble the various components thereof, and a more detailedillustration of a desired notch or spacing 411 to add flexibility anddecrease stiffness, between the base of the device and a support memberof a structure; and FIG. 4( d) is a cross-sectional view thereof,illustrating the internal composition of base isolator 400 in accordancewith the present invention. One or more actuators may be couple tocomponents of base isolator 400 in order to tune base isolator 400 foroptimizing its energy absorbing properties when coupled to a structure.

Base isolator 400, illustrated in FIGS. 4( a)-4(d), comprises of anenergy absorbing material 415 (visible in FIG. 4( d) only), covercomponent 401, layer 402, layer 403, side plates 404, base 405, multiplebolts 406, multiple bolts 407, and a center bolt 408. In the illustratedembodiment, the apparatus is coupled or attached to a structuralcomponent 409, and a structural component 410. These individualcomponents and their possible variations will be discussed in turn,particularly with respect to how some components may be tuned,calibrated or adjusted an automatic disruptive force response system inaccordance with the present invention, for example, system 100 describedabove.

Implementing base isolator 400 with an automatic response system such assystem 100, typically comprises coupling actuators in a manner so thatcritical energy absorbing properties of base isolator 400 may beoptimized—one such energy absorbing property central to the compositionand performance of base isolator 400, is the energy absorbing materialenclosed within base isolator 400.

Energy absorbing material 415 may be any type of energy absorbingmaterial such as filler made of granular elements, for example sand,crushed rocks, specially shaped rocks, or liquid substances, withoutdeparting from the scope of the present invention. In one embodiment,energy absorbing material 415 is made from a granular fill that providesfriction in concert with cover component 401 and its layers 402 and 403.This friction produces a desired dampening to reduce the vibrationscaused by disruptive forces, for example, seismic forces or the force ofan explosion.

An actuator configured to control, adjusts, or tune base isolator 400,may calibrate cover component 401 so as to tune the frictionalproperties which generate the desired damping. For example, and withoutdeviating from the scope of the present invention, an actuator may beconfigured and coupled in a manner so as to pressurize or depressurizecover component 401 in order to alter energy absorbing material 415'sdisplacement, thereby altering energy absorbing material 415'sinteractive forces in concert with cover 401 and its layers 402 and 403.In an exemplary embodiment, this may be accomplished for example, bycompression actuators configured for compressing or depressing sideplates 404.

In another embodiment, energy absorbing material 400 comprises a liquidmixture (which may further comprise other components such as oil,without deviating from the scope of the present invention). In suchembodiment, cover component 401 may further comprise of a spring-loadedchamber (not illustrated), without departing from the scope of thepresent invention. A chamber spring within said chamber (notillustrated) may be utilized to push back displaced energy absorbingmaterial 415, which has been displaced by a disruptive force, back intothe cavity or enclosure where energy absorbing material 415 (e.g. aliquid or oil mixture) is contained during a resting state of the energyabsorbing device.

In such embodiment, an actuator may help control the mechanics of thespring-loaded chamber so as to properly calibrate a desired stiffness ofcover component 401 by introducing or removing a desired amount ofenergy absorbing material 415 in and out of said chamber. For exampleand without deviating from the scope of the present invention, ahydraulic actuator may even replace a spring mechanism to control apressure of said chamber and said enclosure formed by cover component401.

Cover component 401 envelopes or contains energy absorbing material 400by creating a cavity or enclosure between cover component 401 and base405. Cover component 401 is illustrated comprising of multiple layers(i.e. layer 402, and layer 403) however, cover component 401 may beconstructed of a single layer, two layers, or multiple layers, withoutdeviating from the scope of the present invention.

In an exemplary embodiment, cover component 401 comprises of multiplelayers 402 and 403, wherein one layer comprises of a rigid material andthe other layer comprises of a resilient material, for example, andwithout deviating from the scope of the present invention, a resilientmaterial such as rubber and a rigid material such as steel, may beembedded within cover component 401 for additional strength.Furthermore, a layer of a rigid material, for example steel, can befolded to release at a specific force level, a feature that may bedesirable for some applications of an energy absorbing apparatus inaccordance with the present invention.

Cover component 401 may be constructed of one material, a mixture ofmaterials, or may be constructed of multiple layers of differentmaterials bounded, or bonded, together to form cover component 401. Forexample, cover component 401 may be constructed of rubber or neoprenematerials, or a mixture of both, without deviating from the scope of thepresent invention.

In an exemplary embodiment, cover component 401 comprises of a rigidlayer and a resilient layer, (i.e. layers 402 and 403), wherein eachlayer is further reinforced with an additional material (e.g. nylon).For example, and without limiting the scope of the present invention,layer 402 comprises of steel sheet and nylon reinforcements and layer403 comprises of rubber; the sheet steel and nylon being bonded to therubber layer to form cover component 401.

Layers 402 and 403 may be bonded in any configuration; each layer ofdifferent materials may be bonded on the sides surrounding the rubbermaterial, on top of the rubber material, or in any configuration, tobond the steel, nylon and rubber that comprise cover component 401.Furthermore, the thickness of layers 402 and 403 may vary depending ontheir respective materials. For example, and without deviating from thescope of the present invention, the thickness of steel and nylonreinforcements will vary to provide different material propertiesdepending on the intended application (i.e. building reinforcements,military structures, or implementing an energy absorbing system forspecial cargo).

Cover component 401 is typically semicircular in shape (as illustrated);this shape is desired because of its strength and flexibilityproperties, however, cover component 401 may be shaped in a variety offorms—depending on the intended application for such energy absorbingdevice—without deviating from the scope of the present invention.

In one embodiment cover component 401 is triangular in shape; in anotherembodiment cover component 401 is circular in shape; in yet anotherembodiment cover component 401 is shaped like a square (with flatsurfaces creating the cavity which houses energy absorbing material415); Finally, in an embodiment utilizing a resilient component such asa rubber material, the rubber itself may be rectangular, u-shaped, orbox-shaped.

Actuators may be configured in a manner so as to change the height ofcover component 401 without altering base isolator 400's width. Thiscalibration may be desirable in the event a vertically oriented force isexerted on a structure to which base isolator 400 is connected to. Forexample, and without deviating from the scope of the present invention,actuators may be placed between structural component 410 and cover 401on either side of base isolator 400 to adjust or alter cover component401's height without significantly altering side plates 404; naturally,energy absorbing device 415 must be of such composition and configuredin a manner so as to allow for such alterations or calibrations of baseisolator 400.

In each of the aforementioned embodiments, layers 402 and 403 of covercomponent 401 may vary in specification (dimensions, weight, thickness,flexibility, etc.) depending on the material properties required toresist a desired magnitude of force—the thickness of steel and nylonreinforcement for example, may vary, depending on the desired materialproperties necessary to properly restrain displacement of covercomponent 401.

Naturally, such properties will relate to parameter dependent factors,such as stiffness, damping ratio, or bearing displacement desired for aparticular application of the present invention; such measurements anddimensions may be easily calculated with known methods andformulas—formulas and calculations that are presently well known to oneskilled in the art.

By configuring one or more controllers, such as controller 102, toprocess such relevant parameter-dependent factors, including stiffness,damping ratio, or bearing displacement desired for a particularapplication of the present invention, such measurements and dimensionsmay be easily calculated so that one or more controllers may tune baseisolator 400 via the implemented actuators.

Actuators may also be configured to adjust base isolator 400's width.Side plates 404 are ideally made of steel, although other knownmaterials may be utilized, and sandwich cover component 401 in a mannerso as to add frictional forces with base 405 and help generate dampingforces in response to a disruptive force. An actuator configured toclamp side plates 404 may alter the width of cover component 401 andtune said generation of damping forces.

In an exemplary embodiment however, a more desirable configuration maycomprise connecting an actuator to center bolt 408 in a manner so as totune base isolator 400 (i.e. to alter a resonance frequency of baseisolator 400) without the need for multiple actuators.

Center bolt 408 is perpendicular to and positioned between side plates404, running through the cavity containing energy material 400. Thus,the rigidity and displacement capability of energy absorbing material415 may be adjusted by tightening or loosening center bolt 408; ascenter bolt 408 is tightened, for example, side plates 404 are broughtcloser to create a smaller cavity, which is desirable to control thedampening capabilities of the energy absorbing device. Center bolt 408,along with bolts 406 and 407, help to transfer tension and shear forcesaway from the structure. Center bolt 408 may be a typical bolt, aclamping device or any other type of device known in the art that can beutilized to connect side plates 404. Typically, and perhaps moredesirable, center bolt 408 is a typical bolt that is inexpensive yetmade of durable strong material, and several known types of actuatorsmay easily be implemented to interface with bolt 408.

Cover component 401, and (if embodied), side plates 404, are configuredto connect with a base 405 which also helps to transfer forces into thefoundation and away from the remainder of the structure. While covercomponent 401 may be manufactured or molded or constructed in suchmanner as to create a cavity suitable for containment of energyabsorbing material 415, cover component 401 may also be configured torest or be connected with base 405 in such a matter so that base 405completes the desired enclosure or cavity in which energy absorbingmaterial 400 will be contained, without deviating from the scope of thepresent invention. Implementation of actuators thus depends on theconfiguration of the components of a base isolator or energy absorbingdevice.

For example, cover component 401 comprises of layers 402 and 403, whichhave respective ends configured to attach to base 405 with multiplebolts 406. Multiple bolts 406 may also be coupled to one or moreactuators to adjust, calibrate or tune a desired transfer of forces awayfrom a structure to which base isolator 400 is connected to.

Multiple bolts 406 need not be limited to more than one bolt, andmultiple bolts are not the only method of connecting cover component 401to base 405; any other known method may be utilized without deviatingfrom the scope of the present invention. For example, bonding agents maybe utilized, or clamp devices may be utilized which can be adjustabledepending on the desired settings of the device. Typically, multiplebolts 406 are regular adjustable bolts that can be mounted on astructure to connect cover component 401 and base 405 to a structuralcomponent of some structure, such as structure component 409, and may bemore desirable than a clamp device because of practical and economicalconsiderations.

Similarly, multiple bolts 407 may also be utilized to connect covercomponent 401, to a structural component 410. Multiple bolts 407 mayalternatively comprise a single bolt, a clamping device, or some type ofbonding agent capable of securely connecting cover component 401 to astructure, but again, multiple bolts 407 may be more desirable than aclamp device because of practical and economical reasons; furthermore, abonding agent may not be as effective as transferring forces away fromthe structure.

Again, coupling multiple actuators to components such as multiple bolts406, multiple bolts 407, or center bolt 408, may depend on the desiredconfiguration of base isolator 400 and on the application for which baseisolator 400 may be utilized as an energy absorbing device. For example,and without limiting the scope of the present invention, base isolator400 may be coupled to a retaining wall, a foundation for a building,components for an armored vehicle, or any other application which mayrequire energy absorbing properties provided by base isolator 400. Thus,structural components 409 and 410 may be any parts or components of astructure wherein an energy absorbing device may be mounted, such as aframe or a support member of a structure.

Typically however, structural component 409 may be the foundation of abuilding and structural component 410 may be a frame or floor of saidbuilding.

FIG. 4( b) is a side view of an energy absorbing apparatus installedwithin a structure, for example between the floor and foundation of abuilding. FIG. 4( b) illustrates how side plates 404 may sandwich,retain, restrain, or contain cover component 401. From this perspective,layers 402 and 403 of cover component 401 are also visible at the topand bottom of the energy absorbing apparatus, where cover component 401is coupled or attached to the structure with multiple bolts 407 and 406,respectively. Furthermore, one alternative installation feature whichmakes use of a spacing 411 to minimize stiffness to the apparatusperpendicular to the direction of loading is illustrated in this view.This spacing allows for movement to occur when a disruptive force isapplied to an energy absorbing apparatus in a direction parallel tocenter bolt 408. How a structure is affected to such disruptive forcesis further disclose in reference to FIG. 7, disclosing a differentinstallation configuration for a base isolator such as base isolator 400in accordance with the present invention.

FIG. 4( c) is a close-up view of a lower right portion of the energyabsorbing apparatus illustrated in FIG. 4( b), depicting an exemplaryway to assemble the various components of one embodiment of an energyabsorbing apparatus, and a close-up of a desired notch or spacing 411 toadd flexibility and decrease stiffness, between base 405 and a supportmember of a structure, for example structural component 409.

Spacing 411 is an alternative to various methods of achieving thedesired flexibility. Typically, the stiffness of the energy absorbingapparatus, perpendicular to the direction of the loading, is minimal. Inother words, a force applied in a direction perpendicular to side plate404, for example, may cause side plate 404 to move sideways; in suchevent, spacing 411, as illustrated in FIG. 4( c), will allow for thismovement to occur smoothly, thus transferring forces away from thestructure and deviating stress from base 405 and side plates 404.Similarly, such spacing may be desirable at the top of the device wherelayers 402 and 403 make contact.

Nevertheless, spacing 411 is merely an alternative feature and otherknown methods of providing such flexibility may be employed withoutdeviating from the scope of the present invention, for example, otherresilient materials with a flexible property may be used in place ofspacing 411; alternatively, spacing 411 may not be utilized at all butthe stiffness or lack thereof of an energy absorbing apparatus may beaccomplished simply by a particular composition of flexible materialsused in the device's construction. Thus, spacing 411 may or may not beimplemented without deviating from the scope of the present invention.

For example, whether spacing 411 is utilized in the apparatus'sinstallation or not, the stiffness, flexibility or desiredcharacteristics of the device may be altered depending on the manner inwhich the various components are coupled, attached, or bonded together.

FIG. 4( c) also shows a typical way of bonding side plates 404 to base405. In one embodiment, some bonding method or bonding component 412 maybe applied to both base 405 and side plates 404, such as spot welding,to ensure a strong link between the two components allowing the deviceto resist a disruptive force from breaking off side plates 404. Inanother embodiment, a weaker bond may be used as bonding component 412to allow side plates 404 to break off easily, transferring a disruptiveforce away from the structure. Thus, depending on the desiredapplication, various types of bonding methods and materials may be used,or different installation configurations may be employed to provide aparticular range of motion, flexibility or level of stiffness, for anenergy absorbing device in accordance with the present invention.

As mentioned above, several embodiments are disclosed wherein baseisolator 400 may be coupled to one or more actuators to drive multiplebolts 406, multiple bolts 407, or adjust center bolt 408. This tuning ofbase isolator 400 may allow for different ranges of motion, flexibilityor level of stiffness, depending on the disruptive force to which astructure may be subjected to. In yet another embodiment, an actuatormay be implemented to calibrate or tune a level of flexibility orstiffness provided by spacing 411 by replacing space 411 with, forexample, a hydraulic actuator. An actuator in spacing 411 of baseisolator 400 may be able to better respond to a force applied in adirection perpendicular to side plate 404, thereby allowing for thismovement to occur smoothly, thus transferring forces away from thestructure and deviating stress from base 405 and side plates 404.Similarly, such actuator may be desirable at the top of the device wherelayers 402 and 403 make contact.

Again, by implementing one or more actuators to base isolator 400,properties such as stiffness, damping ratio, or bearing displacement,may be altered or calibrated in response to a disruptive force; suchmeasurements and parameters for base isolator 400 may be easilycalculated with known methods and formulas—formulas and calculationsthat are presently well known to one skilled in the art, such as thosediscussed above in relation to controller 102.

The actuators that may be implemented are easily adaptable to fit orinterface with base isolator 400 due to the simple nature of each ofbase isolator 400's components. Because each component of suchembodiment for an energy absorbing device is readily available andcommonly known in the hardware industry (perhaps with the exception ofthe particular energy absorbing material one may desire to implement)the actuators to be implemented with a base isolator in accordance withan exemplary embodiment of the present invention may easily beconfigured to interface with the isolator's various components. FIG. 5(a) and FIG. 5( b), illustrate a more detailed example of an embodimentof such isolator to which known actuators may either be directlyimplemented or easily modified to interface with one or more components.

FIG. 5( a) is an exploded view of an energy absorbing apparatus,displaying its various components and parts. FIG. 5( b) is an elevatedplane view of the same, fully-assembled, energy absorbing device.

In accordance with an exemplary embodiment of the present invention, abase isolator that may be used with the automatic response systemdescribed in the present disclosure is illustrated, to which actuatorsmay easily be implemented to interface with its various components.

In the embodiment illustrated in FIGS. 5( a)-(b), cover component 500comprises of layers 520 and 530. Typically, layer 520 is a rigidmaterial, for example sheet steel, and may be a single layer or multiplelayers bonded to layer 530, typically a resilient material such asrubber. However, as previously mentioned, layers 520 and 530 may bebonded or coupled in different configurations and may comprise differentmaterials. Nevertheless, a rigid material against a resilient materialdo add a desired force which helps limit the displacement of the deviceand thus such configuration of components, that achieves a desiredlimited displacement, may be preferred to other configurations.

Cover component 500 is shown here with side reinforcements, orrespective ends 505, which allow for cover component 500 to be coupledwith base 501 and a structural component such as a foundation byconnecting each component with typical bolts 504 and typical fasteners506. Actuators may constantly adjust bolts 504 so that (for example,after an earthquake) the unit is securely attached to its respectivestructural component.

Similarly, typical bolts 502 and fasteners 503 are utilized to connectcover 500 to a second structural component such as the frame of asuperstructure. Actuators may adjust bolts 502 accordingly during adisruptive event, or during maintenance.

The cavity or enclosure created between cover component 500 and base 501can be filled with any type of material that has an energy absorbingproperty (as discussed above) such as a granular fill, a liquid, an oilbased mixture, crushed sand, or any other type of energy absorbingmaterial that may be displaced upon impact or subjection to a disruptiveforce.

To fully envelope the enclosure between cover component 500 and base501, side plates 508 are connected to both cover component 500 and base501; as explained above, this coupling may be performed by utilizing abonding agent, welding or any other type of method known in the art.Here, bolt 510 is utilized to connect side plates 508, sandwiching covercomponent 500 and creating a frictional force against the energyabsorbing material (not shown) inside the cavity formed thereof. Again,as explained above, bolt 510 may be adjusted to create the rightfriction for the desired damping effect of the device. An actuator maybe able to add or decrease a pressure inside said cavity in order toachieve the desired displacement in response, or in anticipation, to adisruptive force.

Having disclosed the various components of an exemplary embodiment of abase isolator for use with the present invention, we now turn to FIG. 6for an illustration of the workings of such base isolator describedherein.

In particular, FIG. 6 displays a directional displacement effect on oneembodiment of a base isolator for implementation with an automaticdisruptive-force response system, as disruptive forces are applied; forexample seismic forces generated during an earthquake.

As the illustration shows, the energy absorbing device provides a loadpath between the ground and the structure. A disruptive force, such asan impact force, an explosive force, or a seismic force, causes theapparatus to displace, moving from point 601 to point 602 and creating adisplacement.

The displacement is directional in that displacement is parallel to theside plates 603 of the apparatus. Therefore, if the ground moveshorizontal, parallel to side plates 603, base plate 604 moves with theground while the base member 605, (e.g. a superstructure) stays still ormoves in an opposite direction enough to absorb the disruptive force.This movement, or displacement, causes the cover component 606 todisplace, since it is flexible in nature. Inside, the energy absorbingmaterial 607, for example a granular material, will also be displaced.

It is this displacement property that allows the ground to moveindependent from the structure. For example, and without limiting thescope of the present invention, when an energy absorbing apparatus isconnected to the foundation of a structure, the superstructure (that is,the structure built above the foundation) will move independently fromthe foundation of the structure due to the displacement of the energyabsorbing device. Sensor data sent to actuators coupled to suchapparatus will enhance the effectiveness of an energy absorbing deviceby constantly tuning the device during the disruptive event.

Another feature that helps reduce damage to such structure, for examplea building, is the dampening properties of such energy absorbing device.In the exemplary embodiment of a base isolator in accordance with thepresent invention, the dampening properties are created by the frictionbetween the rubber of cover component 606, side plates 603, and energyabsorbing material 607; as friction is created, the device absorbs theenergy from the disruptive force; meanwhile, actuators are constantly(as required and determined by a central controller or processor) tuningthe device for maximizing energy dissipation and or absorption.

Furthermore, a controller coupled to such base isolator, may compensateor take into account any of the limitations that come from the materialsas far as displacement and dampening capabilities; these thresholds andspecifications can be calculated by such controller with known methods,as discussed above.

Other limitations include the following: the rubber is limited indisplacement by the steel sheet—the steel sheet will displace until somelimit, at which point the components will simply restrain movement.Obviously this is desired to prevent the collapse of a structure andmaintain structural integrity. Again, these limitations can becalculated with known methods in the art, and thus controller tuning viaactuators may substantially compensate for such limitations.

Typically, under static conditions, the weight of the structure iscarried by the sheet steel and rubber components that make up the baseisolator, including the filler material. Under displacement, the fillermaterial will still support the vertical load of the structure. Finally,the elastic properties of the components (i.e. rubber, steel sheets, andfiller material), in addition to tuning by one or more coupledactuators, will restore the apparatus to its initial shape or a desiredshape, effective against or in anticipation of an exerted force.

While the disclosed system and method serves to detect disruptive forcesand calculate an adjusted value in order to tune an energy absorbingdevice coupled or attached to a structure, the sensor and controller canbe calibrated to operate at a minimum threshold level for detecting adisruptive force.

For example, if a structure is located in a densely populated and busyarea, the sensor and/or controller may be calibrated to be more or lesssensitive to disruptive forces (e.g. nominal vibrations) around suchstructure. Setting different levels of sensitivity for the sensor andcontroller system may be a desirable feature to avoid responses tonegligible forces. Additionally, civil and structural engineers may findthis system and method useful for monitoring the problems and issuesthat arise in their work that may involve inspections, buildingmaintenance, and remedying structural defects.

Turning next to FIG. 7 and FIG. 8, two exemplary configurations forplacement of various energy absorbing devices coupled to actuators inaccordance with one embodiment of the present invention are illustrated.

More specifically, FIG. 7 is a diagram representing a top view of astructure's support beams, or frame, adapted with several base isolators(i.e. one or more variations of base isolator 400 or base isolator 500coupled to one or more actuators).

While the present description is not intended to limit the disclosedautomatic response energy dissipation system to exclusively implementbase isolators, this example particularly focuses on explaining themanner in which such base isolators (i.e. base isolator 400 or baseisolator 500) may react when activated in response or anticipation of adisruptive force.

The representation of a top view depicts structure 700 comprising ofsupport members 701 (e.g. a frame or support beams for a building),which are coupled to structure 700's foundation 702, resting on variousbase isolators 703, 704, 705, 706, 707, 708, 709, and 710. Each baseisolator is coupled to a corresponding actuator 703 a, 704 a, 705 a, 706a, 707 a, 708 a, 709 a, and 710 a, wherein each actuator is configuredto receive control signals from sensors/controller (system) 750.

Base isolators 703, 704, 708, and 707 may be positioned on supportmembers 701 along a width W of structure 700, and base isolators 705,706, 709 and 710, may be positioned along a length L of structure 700.This configuration is desirable so that structure 700 may withstanddisruptive forces applied from a variety of directions, such as back andforth movements along the length of structure 700 or back and for themovements along the width of structure 700.

For example, and without limiting the scope of the present invention, aforce applied along the width of structure 700 (i.e. parallel to baseisolators 703 and 704) may activate base isolators 703, 704, 708, and707 but not activate base isolators 705, 706, 709 and 710. Similarly, aforce applied along the length of structure 700 (i.e. parallel to baseisolators 705 and 706) may activate base isolators 705, 706, 709 and 710but not activate base isolators 703, 704, 708, and 707. Naturally, aforce that approaches from an angle neither perpendicular nor parallelwith respect to either set of isolators may activate all devicesproportionally, depending on the direction of the disruptive force.

The non-activated devices, during a particular event when a disruptiveforce is applied to structure 700, may comprise of a flexiblecharacteristic or feature that allow for transfer of forces during anon-activation stage of the device. For example, as mentioned above,spacing 411 (see, FIGS. 4( b) and 4(c)) or similar methods (such asusing actuators in spacing 411), which decrease stiffness or increaseflexibility perpendicular to the direction of the displacement load,come into play when some devices are activated but other devices arenot. This feature helps balance out the unidirectional limitation of thedevice which is otherwise desirable to allow for much easiermathematical modeling predictions that make structural engineering aneasier, more efficient task for those skilled in the art.

During a disruptive event such as seismic forces exerted on structure700, system 750 automatically processes and generates appropriatecontrol signals to actuators 703 a, 704 a, 705 a, 706 a, 707 a, 708 a,709 a, and 710 a via a communications medium 760. Each actuator in turnreceives a specified control signal for tuning their respective baseisolator to anticipate or respond in accordance with the structuralrequirements of structure 700. For example, and without limiting thescope of the present invention, tuning the actuators may increasestructure 700's period, alter a base isolator's resonance frequency, orgenerate a damping force to dissipate vibrations created by the seismicevent.

Finally turning to FIG. 8, another exemplary configuration isillustrated wherein base isolators are positioned or distributedthroughout an area 800 wherein said area 800 comprises one or morebuildings. For example, area 800 may comprise of an entire city block,wherein multiple base isolators such as base isolator 400 or baseisolator 500, are configured in a substantially circular orientation805.

Area 800 is typically divided into sectors, and each sector or means ofdividing area 800 may be accomplished in any known manner; however asway of example, area 800 is represented here as comprising fourquadrants 801, 802, 803, and 804. Dividing area 800 into severalsectors, sections, divisions, or quadrants may be desirable to create agrid or means of identifying the location for each individual baseisolator. For example, this may aid a controller sending signals to aparticular base isolator by providing an ‘address’ depending on the baseisolator's location in relation to the grid that makes up area 800.

This configuration may be desirably so that multiple range of motion isprovided for one or more structures that may be erected within area 800.Furthermore, because a number of structures (i.e. several buildingswithin said city block) are all covered by the same system of baseisolators, costs may be distributed among different entities rather thaneach separate structure having to implement its own base isolationsystem.

Configuration 800 may comprise one or more structures (i.e. differentbuildings), which may be present in quadrant 801, quadrant 802, quadrant803 and quadrant 804, however, in alternative environment, configuration800 may comprise of a single structure. Each of the base isolators,which are preferably of the type previously described herein, has anattached actuator connected to a controller and sensor system inaccordance with the present invention. The base isolators are placedstrategically around the structure, as shown by isolators 810, 820, 830,840, 850, 860, 870, 880, 890, 891, 892, and 893 coupled to correspondingactuators 810 a, 820 a, 830 a, 840 a, 850 a, 860 a, 870 a, 880 a, 890 a,891 a, 892 a, and 893 a. Each base isolator responds differentlydepending on the direction of the movement of the disruptive force, andin response to control signals sent from system 888, wherein system 888comprises a controller and sensor system in accordance with the presentinvention.

Although system 888 may communicate or send tuning signals to eachactuator for tuning each base isolator via any known methods withoutdeviating from the scope of the present invention, in an exemplaryembodiment (as illustrated), system 888 utilizes a transceiver 899 towirelessly send control signals and communicate with each device ofconfiguration 800.

System 800 may detect a disruptive event and generate control signals towirelessly tune each device via transceiver 899. If the magnitude of adisruptive force occurs with greater force on the north-east side ofconfiguration 800, for example quadrant 802, base isolators 810, 820,830, and 840 may experience greater displacement than the remaining baseisolators; however every actuator in configuration 800 will be sentsignals to tune each isolator accordingly in a manner so as to absorb ordissipate the energy created by the disruptive force in effect.

Again, in the present disclosure, tune or tuning, as defined in thepresent herein, may refer to (without limitation): a process ofselecting appropriate genetic operators and their respective parametersto suit a problem; a process of changing the parameters of a device or asystem to achieve a specified or improved performance; a process ofestablishing a desired frequency of a system; or a variety ofadjustments, modifications, alterations, or calibration to optimizeperformance of an overall system.

Although configuration 800 is particularly geared and designed for baseisolators such as base isolators 400 or base isolator 500, an energyabsorbing system in accordance with the present invention may include(without limitation): a passive energy control system, an active energycontrol system, a semi-active energy control system, a hybrid controlsystem, or any other type of known energy control system directed atprotecting structural integrity for a variety of applications, withoutdeviating from the scope of the present invention.

Without limiting the scope of the present invention, it may be desirableto implement a base isolator such as base isolator 400 with theautomatic response system disclosed herein. The concept of automaticallytuning an energy absorbing device such as base isolator 400 is that thestiffness of the device will vary based on the time-history of adisruptive event (e.g. an earthquake, high winds, an explosion, etc.)detected by one or more sensors. Sensors then relay a signal to acontroller, which has been configured with the mathematical propertiesfor the structure's mass and stiffness, and computes or processes theideal tuning (stiffness and or damping) for the energy absorbing deviceutilizing well known algorithms or processes.

For example, and without limiting the scope of the present invention, inone possible scenario, a response to a disruptive force the disruptiveforce sends signals to a sensor coupled to a controller. The controllerdirects the actuator to tighten or loosen base isolator 400's centerbolt 408 that holds two steel plates 404 against rubber cover 401 andenergy absorbing material 415. As plates 404 are pulled or pushedtogether by center bolt 408 (i.e. tightened or loosened), the stiffnessand damping is modified for optimum protection of a building. Thisadjustment continues for the entire time-history of the sensor motion ordisruptive event (e.g. earthquake, wind, blast, etc.).

This is an improvement over traditional systems currently in use, whichmay react to light winds and occupancy loads in a manner that causes thebuilding to sway slightly; this sway is often felt by the occupants andcauses an undesirable “sea sick” feeling. Thus, since such systems'sensitivity may not be adjusted, the structures or building whichimplement such technology are frequently affected with undesirablemotion.

The automatically adjusted energy absorbing device (via sensors andactuators) may be tuned to be stiff and eliminate the slightest sway,making the building friendlier to its occupants. Meanwhile, the systemis still capable of responding to a wide range of disruptive motions byadjusting the stiffness of the device, and properly responds to resistthe most extreme disruptive force.

A system and method for adjusting the resonance frequency of an energyabsorbing device attached to a structure has been described. Theforegoing description of the various exemplary embodiments of theinvention has been presented for the purposes of illustration anddisclosure. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching. It is intendedthat the scope of the invention not be limited by this detaileddescription, but by the claims and the equivalents to the claims.

What is claimed is:
 1. An automatic energy dissipation system,comprising: a sensor for detecting a disruptive force applied to abuilding; a processor connected to the sensor, configured fordetermining a control signal based on a sensing data received from thesensor; an energy absorbing device, comprising an enclosure with avariable stiffness, the enclosure configured to house an energyabsorbing material; and an actuator, coupled to said processor andconnected to the energy absorbing device, for adjusting the rigidity ofthe enclosure, wherein adjusting the rigidity of the enclosure resultsin tuning the energy absorbing device based on the control signalgenerated by the processor in order to alter a resonance frequency ofsaid building.
 2. The system of claim 1, wherein the energy absorbingdevice is installed between a superstructure of the building and afoundation of the building, in a manner so that the superstructure isisolated from the foundation.
 3. The system of claim 1, wherein thetuning of the energy absorbing device comprises altering a resonancefrequency of the building to reduce a structural response to thedisruptive force applied to the building.
 4. The system of claim 1,wherein the tuning of the energy absorbing device comprises generating adamping force to reduce a structural response to the disruptive forceapplied to the building.
 5. The system of claim 4, wherein the dampingforce comprises viscous damping.
 6. The system of claim 4, wherein thedamping force comprises hysteretic damping.
 7. The system of claim 4,wherein the energy absorbing device is configured as a variable frictiondamper.
 8. The system of claim 4, wherein the energy absorbing device isconfigured as a variable viscous damper.
 9. The system of claim 1,wherein the energy absorbing device is a base isolator configured for:adjusting a resonance frequency of the building; and generating adamping force to reduce a structural response to the disruptive forceapplied to the building.
 10. The system of claim 9, wherein the baseisolator further comprises: a base adapted to attach to a support memberof the building; and a cover coupled to the base in a manner so as toform the enclosure, wherein the cover is adapted to attach to the baseand the building; and wherein the enclosure is coupled to the actuatorin a manner so that the rigidity of the enclosure may be controlled byactivating the actuator.
 11. The system of claim 10, wherein the coverof the base isolator further comprises: a rigid layer; a resilientlayer; and a plurality of side plates; wherein the rigid layer and theresilient layer are substantially semicircular in shape, havingsubstantially the same center and having respective ends configured toattach to the base; and wherein the rigid layer acts as a restrainingmaterial for the resilient layer when the disruptive force is applied tothe cover.
 12. The system of claim 11, wherein the resilient layer ofthe cover is securely sandwiched between the side plates, the sideplates being coupled to the actuator to adjust the damping force whenthe actuator is activated for the tuning.
 13. The system of claim 11,wherein the cover is coupled to the support member of the building neara top portion of the semicircular shape of the rigid and resilientlayers.
 14. The system of claim 13, wherein the respective ends of thecover are coupled to a foundation of the building to provide a constantfactor of initial and sliding friction between the rigid layer and theresilient layer for transferring tension and shear forces away from thebuilding.
 15. The system of claim 14, further comprising a plurality ofactuators adapted to attach to the cover at the respective ends and thetop portion of the semicircular shape for: tuning the constant factor ofinitial and sliding friction between the rigid layer and the resilientlayer; and tuning the transferring tension and shear forces away fromthe building.
 16. The system of claim 10, wherein the energy absorbingmaterial enclosed in the cover of the base isolator further comprises agranular material, which provides vertical strength and allows forsideways slip when the disruptive force is applied.
 17. The system ofclaim 10, wherein the energy absorbing material enclosed in the cover ofsaid base isolator further comprises a liquid, which provides verticalstrength and allows for sideways slip when said disruptive force isapplied.
 18. The system of claim 17, wherein the cover further comprisesa valve to transfer the liquid into a spring loaded chamber whenever thedisruptive force is applied; the spring loaded chamber having a springpositioned to push the liquid back into the cover whenever the cover isrelieved from the disruptive force.